Merge changes I3ef1ad8c,I0bbbba1a,Ife107fb6,Ia420b766

* changes:
  Switch Dex from byte[] to ByteBuffer for backing store. Part 2.
  Move dex utilities from dalvik/dx to libcore/dex
  Mechanical refactoring of dx into two parts.
  Change com.android.dx.io.Annotation to use EncodedValue